# Reading complex numbers from file dump

**URL:** <https://www.ruby-forum.com/t/reading-complex-numbers-from-file-dump/235990>\
**Category:** GNU Radio\
**Created:** [July 29, 2013, 3:39pm UTC](https://www.ruby-forum.com/t/reading-complex-numbers-from-file-dump/235990 "2013-07-29T15:39:44Z")\
**Posts on this page:** 3\
**Page:** 1

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**Author:** ![addis\_a](https://www.ruby-forum.com/letter_avatar_proxy/v4/letter/a/c4cdca/32.png) [@addis\_a](https://www.ruby-forum.com/u/addis_a)\
**Post date:** [July 29, 2013, 3:39pm UTC](https://www.ruby-forum.com/t/reading-complex-numbers-from-file-dump/235990/1 "2013-07-29T15:39:44Z")

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Hi,

I have created a file dump with samples from USRP output. Samples are  
in  
gr\_complex format. Now I want to read data from the file to compute FFT.  
How can I read complex numbers in python from this binary file?

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**Author:** ![Manu\_T\_S](https://www.ruby-forum.com/letter_avatar_proxy/v4/letter/m/ea5d25/32.png) [@Manu\_T\_S](https://www.ruby-forum.com/u/Manu_T_S)\
**Post date:** [July 29, 2013, 4:47pm UTC](https://www.ruby-forum.com/t/reading-complex-numbers-from-file-dump/235990/2 "2013-07-29T16:47:31Z")

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On Mon, Jul 29, 2013 at 9:38 AM, Manu T S [removed\_email\_address@domain.invalid](mailto:removed_email_address@domain.invalid) wrote:

> Hi,
> 
> I have created a file dump with samples from USRP output. Samples are in  
> gr\_complex format. Now I want to read data from the file to compute FFT. How  
> can I read complex numbers in python from this binary file?
> 
> –  
> Manu T S

There are examples of this in gr-utils/python/utils . One of the  
scripts even plots the fft for you.

-Nathan

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<div class="post-metadata">

**Author:** ![Manu\_T\_S](https://www.ruby-forum.com/letter_avatar_proxy/v4/letter/m/ea5d25/32.png) [@Manu\_T\_S](https://www.ruby-forum.com/u/Manu_T_S)\
**Post date:** [July 29, 2013, 4:56pm UTC](https://www.ruby-forum.com/t/reading-complex-numbers-from-file-dump/235990/3 "2013-07-29T16:56:53Z")

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On Mon, Jul 29, 2013 at 9:38 AM, Manu T S [removed\_email\_address@domain.invalid](mailto:removed_email_address@domain.invalid) wrote:

> Hi,
> 
> I have created a file dump with samples from USRP output. Samples are in  
> gr\_complex format. Now I want to read data from the file to compute FFT. How  
> can I read complex numbers in python from this binary file?
> 
> –  
> Manu T S

See here:  
[http://gnuradio.org/redmine/projects/gnuradio/wiki/FAQ#What-is-the-file-format-of-a-gr\_file\_sink](http://gnuradio.org/redmine/projects/gnuradio/wiki/FAQ#What-is-the-file-format-of-a-gr_file_sink)

There are also a handful of plotting tools in gr-qtgui/apps that read  
from files using the scipy.fromfile function mentioned in the above  
FAQ. You can use these for references.

Tom